[Samba] calculating uidnumber

[Torben Thomsen]

Hi,
I'm building my system on a LDAP backend, but I wan't to have full 
control over the user creation-process. I have developed a backend in 
php, to handle most of my needs. Except for calculating the uidnumber, 
from where i calculate sambaSID...
My question is, can I call a function somewhere that returns the next 
uidnumber/gidnumber? or do I have to look at idmap?

Thanks
Torben